Vacuum insulated door construction

ABSTRACT

A method of fabricating a refrigerator cabinet or door includes forming a wrapper and an inner liner. The method further includes forming a vacuum insulated core comprising a permeable core material that is disposed inside an impermeable envelope. A sheet of prefabricated compressible foam material is positioned between the vacuum insulated core between the inner door liner and/or the door wrapper. The prefabricated compressible foam material may be cut from a sheet of foam having substantially uniform thickness prior to fabrication of the refrigerator door. The foam compresses to accommodate differences in spacing between the vacuum insulated core and the door wrapper and/or the door liner.

BACKGROUND OF THE INVENTION

Refrigerators typically include a refrigerated cabinet having one or more openings that can be selectively closed off by doors that are movably mounted to the cabinet. The doors are typically insulated, and seal off the openings when in a closed position. A known type of construction utilized in fabricating refrigerator cabinets and doors includes an outer wrapper and inner liner having an interior cavity or space that is filled with insulating foam. The foam may comprise a polyurethane foam that is injected into the space after the wrapper and liner are interconnected. The foam expands to fill the interior space prior to curing.

Another type of insulated cabinet construction includes vacuum insulated internal panels. Vacuum insulated panels provide improved insulating properties whereby the cabinet walls can be thinner, yet retain the same insulation properties. However, known vacuum insulated refrigerator cabinet and door constructions may suffer from various drawbacks.

SUMMARY OF THE INVENTION

A method of fabricating a refrigerator cabinet or door includes forming a wrapper having a peripheral edge portion. An inner liner having a peripheral edge portion is also formed. The wrapper and liner may comprise an outer door panel (“door wrapper”) and an inner door liner. The method further includes forming a vacuum insulated core comprising a permeable core material that is disposed inside an impermeable envelope. The envelope is evacuated to form a vacuum inside the envelope. A sheet of prefabricated compressible foam material is positioned between the vacuum insulated core between at least one of the inner door liner and the door wrapper. The method includes securing at least a portion of the peripheral edge portion of the door wrapper to the peripheral edge portion of the inner door liner with the vacuum insulated core positioned between the door wrapper and the inner door liner. The prefabricated compressible foam material may be cut from a sheet of foam having substantially uniform thickness prior to fabrication of the refrigerator door. The foam compresses to accommodate differences in spacing between the vacuum insulated core and the door wrapper and/or the door liner. Because the space between the vacuum insulated core and the wrapper and the space between the insulated core and the liner is preferably quite small to provide a thinner door construction, it is difficult to inject conventional foams (e.g. polyurethane) into this limited space. The use of a prefabricated compressible foam sheet eliminates gaps that would otherwise exist, and also provides support for the wrapper and/or liner to reduce flexing/bending that could otherwise occur due to a gap between, for example, the door wrapper and the vacuum insulated core.

These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a refrigerator;

FIG. 2 is an exploded isometric view showing a refrigerator door having a vacuum insulated core and one or more prefabricated foam sheets;

FIG. 3 is an isometric view showing a vacuum insulated core prior to folding into a three dimensional shape as shown in FIG. 2;

FIG. 4 is a fragmentary cross sectional view taken along the line IV-IV; FIG. 3;

FIG. 5 is a partially schematic cross sectional view of the refrigerator door taken along the line V-V; FIG. 1; and

FIG. 6 is a partially schematic cross sectional view of a refrigerator door having a vacuum insulated core and preformed foam sheet.

DETAILED DESCRIPTION

For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in FIG. 1. However, it is to be understood that the disclosed subject matter may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

With reference to FIG. 1, a refrigerator 1 includes an insulated cabinet 2 having internal spaces 4 and 6 with openings 8 and 10, respectively on a front side 12 of cabinet 2. In the illustrated example, the interior space 4 comprises a fresh food refrigerated space that can be accessed by opening one or both doors 14 and 16, and the interior space 6 comprises a freezer compartment that can be accessed by opening drawer 18. Drawer 18 includes an insulated front panel 20. It will be understood that the term “door” as used herein generally refers to a movable door (e.g. doors 14 and 16) or an insulated panel 20 on a movable drawer 18. It will be understood that the construction/method of fabricating door 16 as described herein is equally applicable to the door 14 and front panel 20 of drawer 18.

With further reference to FIG. 2, door 16 includes an outer skin or wrapper 22, a liner 24 and a vacuum insulated core 26. As discussed in more detail below, a prefabricated foam sheet 28 may be positioned between liner 24 and vacuum insulated core 26. A prefabricated foam sheet 30 may also be positioned between the wrapper 22 and vacuum insulated core 26. Door 16 may include only foam sheet 28, only foam sheet 30, or both foam sheets 28 and 30.

Outer wrapper 22 may comprise sheet metal or polymer that is formed to provide a desired 3D shape utilizing known processes. The wrapper 22 may include a central area 32 that is generally planar, and side walls 34A-34D that extend transversely from the central area 32. The side walls 34A-34D may include inwardly-extending flanges 36A-36D that are configured to interconnect with liner 24. The wrapper 22 may optionally include one or more openings 38 that may be utilized to mount a user display 40 and/or an ice and/or water dispenser 42 (FIG. 1).

Liner 24 is preferably made by thermoforming a sheet of polymer material utilizing known thermoforming. Liner 24 may also be made utilizing an injection molding process. The liner 24 includes a central portion 44 and sidewall portions 46A-46D. The side walls 46A-46D may include connecting structures or flanges 48A-48D that are configured to engage the flanges 36A-36D and/or side walls 34A-34D of wrapper 22. The configurations of the peripheral edge portions 50 and 52 of wrapper 22 and liner 24 may have various known configurations, and are generally configured to be interconnected to one another in a known manner.

The vacuum insulated core 26 may include a central area 54 and side walls 56A-56D. With further reference to FIGS. 3 and 4, the vacuum insulated core 26 may be fabricated from a flat sheet of core material 26A having flaps 58A-58D that are folded along fold lines 60A-60D, respectively to form side walls 56A-56D, respectively. With reference to FIG. 4, the panel 26A comprises a permeable core material 62 that is disposed inside an impermeable envelope 64 that is sealed along a seam 66. The envelope 64 is evacuated to form a vacuum. In a preferred embodiment, the core material comprises fiberglass, silica powder, or other suitable material, and the envelope 64 comprises one or more layers of foil and/or polymer. V-shaped notches 68A-68D may be formed utilizing a V-shaped forming tool 70 to thereby provide fold lines 60A-60D. As discussed in more detail below, additional layers of core material 90 may be utilized to provide increased thickness in specific regions if required for a particular application.

Referring again to FIG. 2, the vacuum insulated core 26 is configured to fit closely within wrapper 22, with side walls 56A-56D of vacuum insulated core 26 being disposed directly adjacent, but inside side walls 34A-34D, respectively, of wrapper 22. Liner 24 is configured to fit within vacuum insulated core 26 in a nesting manner, with central portion 44 of liner 24 disposed immediately adjacent central area 54 of vacuum insulated core 26, and with side walls 46A-46D of liner 24 being disposed adjacent and inside of, side walls 56A-56D of vacuum insulated core 26.

Due to manufacturing tolerances, and the like, gaps may be present in at least some regions between liner 24 and vacuum insulated core 26. Similarly, gaps may also exist between wrapper 22 and vacuum insulated core 26 in some regions. To account for such gaps, prefabricated foam sheet 28 and/or prefabricated sheet 30 may be positioned between vacuum insulated core 26 and liner 24 and/or between vacuum insulated core 26 and wrapper 22. The prefabricated foam sheets 28 and 30 preferably comprise a compressible foam material having a thickness of about 0.060-1.0 inches, and more preferably about 0.125-0.375 inches. The foam sheets 28 and 30 may comprise a known foam material that is prefabricated in sheets having uniform thickness, and the sheets 28 and 30 may be cut to size as required for a particular application. Examples of suitable foam materials include polyethylene, EVA (Ethylene-vinyl acetate) and polyurethane. The prefabricated foam sheets 28 and 30 preferably have sufficient stiffness to significantly reduce or prevent flexing of liner 24 and/or wrapper 22, respectively if a user applies an out of plane force to the liner 24 or wrapper 22. However, prefabricated foam sheets 28 and 30 also preferably have sufficient resilience/compressibility to permit some compression during the assembly process to thereby account for variations in the gap between liner 24 and core 26, and variations in the gap between wrapper 22 and core 26. Typically, the gaps between the components are selected to be the same size or smaller than the thicknesses of sheets 28 and 30 even if the gaps are at a maximum possible size due to tolerances in the components such that sheets 28 and 30 are compressed at least somewhat and completely fill the gaps.

During assembly, the wrapper 22 may be positioned in a lower tool or fixture 72. If a prefabricated foam sheet 30 is to be installed between vacuum insulated core 26 and wrapper 22, the prefabricated foam sheet 30 is cut to size. The prefabricated foam sheet may optionally be adhesively attached to the wrapper 22 and/or the vacuum insulated core 26. The adhesive may comprise hot melt adhesive, two-part adhesive, or other suitable adhesive. The prefabricated foam sheet 30 may be sized and configured such that an edge portion 78 of foam sheet 30 is folded along a rectangular fold line 76 during assembly whereby the edge portion 76 is disposed between side walls 34A-34D of wrapper 22 and side walls 56A-56D of vacuum insulated core 26. It will be understood that the prefabricated foam sheet 30 may be cut to remove corner portions of sheet 30 to form flaps to prevent bunching/overlap at the corners in a manner that is similar to the flaps 58A-58D of vacuum insulated core material 26A as shown in FIG. 3.

If a prefabricated foam sheet 28 is to be utilized in the assembly process, the foam sheet 28 is cut to size, and positioned between liner 24 and vacuum insulated core 26. The foam sheet 28 may be adhesively secured to liner 24 and/or to vacuum insulated core 26. The adhesive may comprise hot melt adhesive, two-part adhesive, or other suitable adhesive. The foam sheet 28 may also be cut and folded along fold line 80, whereby the edge portion 82 of prefabricated foam sheet 28 may be positioned between side walls 56A-56D of vacuum insulated core 26, and side walls 46A-46D of liner 24.

An upper tool or fixture 74 may then be utilized to press the wrapper 22 and liner 24 together. The lower tool 72 and upper tool 74 may be configured to ensure that the peripheral edge portions 50 and 52 of wrapper 22 and liner 24 are engaged with one another. The peripheral edge portions 50 and 52 may be sealed and/or interconnected utilizing various suitable known techniques. The assembled door may then be removed from the fixtures 72 and 74.

With reference to FIG. 5, a door 16A includes a wrapper 22A, liner 24A, and a vacuum insulated core 26A. The door 16A includes a prefabricated foam sheet 28A, and may also optionally include a prefabricated foam sheet 30A. The wrapper 22A is preferably formed from sheet metal (e.g. stainless steel) utilizing known metal forming processes, and the inner liner 24A is formed from a polymer material. The liner 24A may be fabricated by thermoforming a sheet of polymer material. The peripheral edge portion 50A of wrapper 22A comprises an inwardly-extending flange. The peripheral edge portion of liner 24A comprises an outwardly-extending flange 52A that overlaps the flange 50A of wrapper 22A. During assembly, the flanges forming the peripheral edges 50A and 52 are interconnected and sealed utilizing known processes.

With further reference to FIG. 6, a refrigerator door 16B includes a metal wrapper 22B, and a polymer liner 24B. Liner 24B may be formed from a sheet of polymer material utilizing a thermoforming process. A prefabricated foam sheet 28B is positioned between the liner 24B and the vacuum insulated core 26B. A prefabricated foam sheet 26B may optionally be positioned between wrapper 22B and vacuum insulated core 26B. The vacuum insulated core 26B includes side wall portions 84 and 86. The side wall portions 84 have an increased thickness “T,” and fit within side walls 88 of wrapper 22B. The increased thickness of side wall 84 may be formed by stacking an additional strip 90 (FIG. 3) of vacuum insulated core material to the side walls of the vacuum insulated core 26B. The end portion 86 of the side wall may comprise a single layer of vacuum insulated core material. For example, the flaps 58A-58D (FIG. 3) may have a width “W1,” and the strips 90 may have a width “W2” that is significantly less than the width “W1.”

Referring again to FIG. 6, the liner 24 may include an end portion 92 that is U-shaped or J-shaped, whereby the end portion 92 extends around the end portion 86 of the side walls of vacuum insulated core 26. During assembly, the peripheral edge portion 50B of wrapper 22B is sealed/attached to peripheral edge portion 52B of inner liner 24B. The peripheral edge portions 50B and 52B may comprise overlapping flanges that are pressed together by upper and lower tool fixtures 74, 72, respectively (FIG. 2) in a known manner.

It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present disclosure, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise. 

What is claimed is:
 1. A method of fabricating a refrigerator door, the method comprising: forming a door wrapper having a central portion and a peripheral edge portion; forming an inner door liner having a central portion and a peripheral edge portion; forming a vacuum insulated core comprising a permeable core material that is disposed inside an impermeable envelope, wherein the envelope has been evacuated to form a vacuum inside the envelope, wherein the vacuum insulated core is sized and shaped to form gaps between the vacuum insulated core and at least one of the central portion of the door wrapper and the central portion of the door liner; positioning a sheet of prefabricated compressible foam material between the vacuum insulated core and at least one of the central portion of the inner door liner and the central portion of the door wrapper; pressing the central portions and the peripheral edge portions of the door wrapper and the inner door liner together using upper and lower tools whereby at least a portion of the sheet of compressible foam material positioned between at least one of the central portion of the inner door liner and the central portion of the door wrapper is compressed and fills the gaps; and securing at least a portion of the peripheral edge portion of the door wrapper to the peripheral edge portion of the inner door liner with the vacuum insulated core positioned between the central portion of the door wrapper and the central portion of the inner door liner while the central portions and the peripheral edge portions of the door wrapper and the inner liner are pressed together by the upper and lower tools.
 2. The method of claim 1, wherein: the sheet of compressible foam material has a uniform thickness prior to assembly of the refrigerator door.
 3. The method of claim 1, wherein: the sheet of compressible foam material is sandwiched between the vacuum insulated core and the inner door liner.
 4. The method of claim 3, wherein: the door wrapper and the inner door liner have rectangular perimeters that are substantially equal in size and shape; the sheet of compressible foam material has a rectangular perimeter disposed adjacent the rectangular perimeters of the door wrapper and the inner door liner.
 5. The method of claim 1, wherein: the sheet of compressible foam material is sandwiched between the vacuum insulated core and the door wrapper.
 6. The method of claim 1, wherein: the sheet of compressible foam material has an initial thickness, before fabrication of the refrigerator door, of about 0.125 inches to about 1.0 inches.
 7. The method of claim 1, wherein: the door wrapper is fabricated from sheet metal; the inner door liner is fabricated by thermoforming a polymer sheet.
 8. The method of claim 1, wherein: the vacuum insulated core is folded to form a 3D shape.
 9. The method of claim 1, wherein: the sheet of compressible foam material is adhesively secured to at least one of the vacuum insulated core, the door wrapper, and the inner door liner.
 10. The method of claim 9, wherein: adhesive is applied to at least one of the sheet of compressible foam material, the door wrapper, and the inner door liner, before the peripheral edge of the door wrapper is secured to the peripheral edge of the inner liner.
 11. A method of fabricating a refrigerator door, the method comprising: forming a door wrapper having a central portion and a peripheral edge portion; forming an inner door liner having a central portion and a peripheral edge portion; forming a vacuum insulated core comprising a permeable core material that is disposed inside an impermeable envelope, wherein the envelope has been evacuated to form a vacuum inside the envelope, wherein the vacuum insulated core is sized and shaped to form gaps between the vacuum insulated core and at least one of the central portion of the door wrapper and the central portion of the door liner; positioning a sheet of prefabricated compressible foam material between the vacuum insulated core and at least one of the central portion of the inner door liner and the central portion of the door wrapper; pressing the central portions of the door wrapper and the inner door liner together using upper and lower tools whereby at least a portion of the sheet of compressible foam material positioned between at least one of the central portion of the inner door liner and the central portion of the door wrapper is compressed and fills the gaps; securing at least a portion of the peripheral edge portion of the door wrapper to the peripheral edge portion of the inner door liner with the vacuum insulated core positioned between the central portion of the door wrapper and the central portion of the inner door liner while the central portions of the door wrapper and the inner liner are pressed together by the upper and lower tools; and the vacuum insulated core includes a generally flat central portion and a pair of spaced apart side walls extending transversely from the central portion whereby the vacuum insulated core is generally U-shaped in cross section.
 12. The method of claim 11, wherein: the inner door liner has spaced apart side walls extending transversely from the central portion whereby the inner door liner has a U-shape in cross section, and wherein the inner door liner rests inside the vacuum insulated core.
 13. The method of claim 12, wherein: the sheet of compressible foam material is disposed between the inner door liner and the vacuum insulated core and includes a central portion disposed between the central portions of the vacuum insulated core and the inner door liner, and edge portions that are disposed between the side walls of the vacuum insulated core and the inner door liner. 